Adjustable choke means for shotguns



June 1952 w. J. HOZA 2,600,874

ADJUSTABLE CHOKE MEANS FOR SHO'IGUNS Filed June '7, 1947 2 SHEETS-SKEET l mug!!! 711 INVENTOR. l V/LL/AH J H02.

June 17, 1952 w. J. HOZA 2,600,874

ADJUSTABLE CHOKE MEANS FOR SHOTGUNS Filed June '7, 1947 2 SHEETSSHEET 2 INVENTOR. W/ZZl/IM J f/oz/v.

Patented June 17, 1952 UNITED STATES PATENT OFFICE ADJUSTABLE CHOKE MEANS FOR SHOTGUNS 14 Claims.

This invention relates to adjustable choke means and more particularly to a mechanism for selectively choking the barrels of firearms, such as shotguns and the like, for obtaining a desired pattern of the shot at the target.

An object of this invention is to provide a choke adjusting mechanism which is particularly adapted for automatic shotguns of conventional design and by means of which the choke adjustment may be controlled by the user of the gun through movement of the forestock without changing the position of the hand while holding and aiming the gun at the target.

A further object of the invention is to provide a mechanism which will permit the adjustment of the choke for difierent pattern of shot and by means of which a desired pattern may be selected previously to each operation of firing the gun.

Further objects and advantages of this invention will be more clearly understood from the following description and from the accompanying drawings, in which:

Fig. l is a side view, partially in central vertical section, of a portion of a gun barrel for an automatic shotgun of conventional form, showing an embodiment of the invention.

Fig. 2 is an enlarged side view, partially in central vertical section, of the choke operating mechanism used on said gun.

Fig. 3 is a rear end view, in vertical section,

illustrating the operation of the lock releasing mechanism.

Fig. 4 is a rear end view, in vertical section, on line 4-4 of Fig. 2.

Fig. 5 is an enlarged elevational fragmentary plan view, partially in section, of the front end of the operating mechanism.

Fig. 6 is a similar view showing the mechanism in a different position.

Fig. 7 is a similar view showing the said mechanism in a further position.

Fig. 8 is a side view. partially in central vertical section, of the front portion of the operating mechanism, showing a modified form of my invention.

Fig. 9 is an enlarged fragmental view showing a modified form of a lock mechanism.

In the embodiment of my invention shown in the drawings, the numeral 4 denotes the barrel and 5 the forestock of a shotgun having a muzzle portion 6 with a plurality of slits 1 therein permitting opening and closing of said muzzle portion to a degree suflicient to provide the required changes in the size of the bore of said muzzle for the range of sizes of the patterns desired for the shot when it reaches the target.

The exterior of said muzzle portion is tapered at 8 so that it will converge towards the end of the muzzle. A sleeve 9 is slidably mounted over the tapered portion of said muzzle and said sleeve has an internal screw thread II) which cooperates with a thread II at the forward end portion of a channeled tie bar I2 that extends rearwardly along the bottom of the barrel and has rigidly secured, at its rear end, a bracket I3.

As commonly understood by those skilled in the art, the muzzle of the gun may be choked to difierent degrees by sliding the sleeve 9 rearwardly on the muzzle 6. Such sliding movement will permit the tapered portion of the sleeve to close the portions of the muzzle between the slits I and thereby choke the muzzle. By rotating the sleeve 9 upon the bar I2, the cooperating threads I0 and II will permit adjustment of the sleeve relatively to the bar so that the device may be calibrated for choking the bore of the barrel, at the muzzle, to predetermined sizes upon operation of my improved mechanism as hereinafter described.

In the embodiment herein illustrated, my improved choking mechanism is shown as incorporated in a portion of the recoil mechanism of an automatic shotgun of conventional design which, as illustrated, includes an anchoring bracket I4 that is rigidly secured to the barrel 4 to slidably support a tubular magazine I5 that extends forwardly through said bracket and has a cap I8 threaded to the forward end thereof. The bracket I4 is provided with an annular tapered seat I6 which receives the tapered portion of a recoil ring I! slidably mounted on the said magazine I5. The flat face of the recoil ring abuts the end of a friction ring II-a which is slidable on the magazine and is urged into frictional engagement therewith by means of an annular spring member I'I-b. The members I'I-a and H4) constitute the conventional braking mechanism incorporated in automatic shotguns which lessens the jolting effect on the recoil spring Il-c as the barrel of the gun recoils when the firearm is discharged.

A sleeve I9 is slidable over the magazine I5 and is securely fastened in the bracket I4 against a shoulder 20. The end of the sleeve I9 engages the end of a collar I9-a which is secured to the cap I9 and surrounds the front end portion of said magazine. The said sleeve I9 extends through and is slidable in the bracket l3 and is provided with an annular stop ring I9-b which is securely fastened thereto. An expansion spring 2| is provided between the bracket I4 and the bracket I3 for forcing the bracket forwardly against the stop ring I94) and thereby causing the bar I2 to move the choke sleeve 9 forwardly on the muzzle 6 for permitting the said muzzle to open into normal position.

The bracket i3 is slotted at 22 to receive a locking spring 23 which is carried by said bracket l3 and embraces the sleeve IS. The said sleeve I9 is provided with notches 2425 at the opposite sides thereof and with a slot 26 in the top thereof. A groove 21, which is wider than the lock spring 23, extends from the slot 26 into the notch 25 and a narrower groove 28 extends from said slot into the notch 24. It will be noted that the rear sides of said grooves 21-28 are in alignment, while the forward sides thereof are in different positions along the axis of the sleeve 19 in order to provide a stop shoulder 2'I-a and a separate stop shoulder 28a spaced rearwardly therefrom.

A look operating member in the form of a lever 29 is pivotally mounted within the forestook on a shaft 3|] which extends through a hub 3;! of; the lever. The said lever depends downwardly, through the slot 26 in the sleeve l9 and the Slot l-a in the tube l5 into position to abutthe end of an adjusting screw 32 that projects rearwardly from the cap I8. And a lock operating extension 33 extends rearwardly from the lever 29 to a position below and between the opposite ends 2'3-a of the lock spring 23, as clearlyshown in Fig. l of the drawings; the said ends being bent outwardly to provide camming surfaces against which the extension 33 will slide for separating the, locking spring as will be hereinafter described.

I A stop screw 34 is threaded into the bracket I3 and projects forwardly with the end thereof adapt d to abut the hub 3|. This screw is adjustable so, as to. engage with said hub 3| at the proper time forthe proper operation of the lookin Sp g 23.

The extension 33 on the lever 29 is normally retained in a downward or horizontal position to permit closing of the locking spring 23; by suitable means, such as a spring 35, which resiliently urges the lever 29 against the end of the. adjustable screw 32 and preferably through a sliding plug or capv 3,6 which engages the end of said spring. In the embodiment shown, the spring 3.5. is a cartridge spring which forms a part of the conventional mechanism of the automatic shotgun shown but which is conveniently utilized herein for the operation of the, lever 29, although other means may be used therefor if desired.

Theoperation of the above described mechanism is, as. follows:

The mechanism is normally in the first position, which is illustrated in Figs. 2 and 5, wherein the bracket I3. is urged into engagement with the. stop ring I9-b by the spring 2| and in which position the. tapered sleeve 9 allows the muzzle, to expand to. its normal, fully opened condition. In this position, the extension 33 on the lever is positioned below and between the ends, 23-11 of the spring 23 and contained within the slot 26 in the sleeve l9 to thereby permit the locking spring 23; to close around the sleeve I9.

Assuming that it is desired to adjust the muzzle 6. to the second position, for the predetermined minimum amount of choke permitted by the mechanism, and that the said mechanism is in the first, or normal, position as above described, the forestock is pulled rearwardly to cause the hub 3|, through its engagement with the screw 34, to move the bracket I3. and, through the. bar 2, the sleeve 9. rearwardly until the spring 23 snaps into the locking groove 21, as clearly shown in Fig. 6, to thereby locate the sleeve 9 in the second position wherein the muzzle 6 will be closed for the first degree of choke.

Upon firing the gun with the choke mechanism in said second position, the force of the discharge will cause the barrel 4 to recoil and carry with it the bracket [4 which slides rearwardly along the magazine, with its associated parts [1, ll-a and l'l-b, against the tension of the spring I1-c. Since the sleeve 19 is fastened to the bracket M, the rearward movement of the bracket will pull the sleeve [9 rearwardly and, through engagement of the spring 23 with the shoulder 27-a and the sides of the slot 22 in the bracket 13, cause the bracket and the bar l2, with the tapered sleeve 9 attached thereto, to move, rearwardly as a unit with the barrel 4 and Without affecting the choke adjustment in any way.

When it is desired to adjust the mechanism for the third position or full degree of choke, the forestock 5 is merely moved further back until the lock ring 23 snaps into the position shown in Fig. 7, wherein the other side of the ring will rest within the groove 28 and against the forward shoulder 28-a thereof and said shoulder will provide the stop to locate the choke adjusting sleeve for the second position and absorb the force caused by the recoil of the gun upon firing as hereinbefore described.

The bore may be returned to normal after each firing of the gun by simply moving the forestock forwardly into abutment with the flange l8-a of the cap I8, and the setting of the choke for the desired degree may then be again selected by the operation of the mechanism as above described.

My novel choke adjusting means permits setting of the mechanism for the desired degree of choke from an aiming position, thereby facilitating the operation of the gun and enabling the person using the gun to quickly select and adjust the choke without removing his eyes from the target. 7

It will be understood that, when the forestock 5 is moved forwardly against the stop shoulder Ill-a as shown in Fig. 1, the lever 29 will be carried therewith so that it will abut the end of the screw 32 and thereby cause the said lever torock and lift the extension 33 to open the lock spring 23. As the lock spring is opened and thereby removed from the slots 21 and 2-8, the spring 2| will forcethe bracket l3 forwardly to the position shown in Fig. 1, wherein it will be stopped by abutment of the bracket. l3-w-ith the stop ring l9-b. The desired amount of choke onthe muzzle 6 may then be easily obtained by simply pulling the forestock- 5 rearwardly, against thetension of the spring 2|, until the lock spring 23 snaps, into the proper position, which maybe in back of; the shoulder 21-11 for the second position, or in back of the shoulder 28- -11 for the third position of said mechanism; the first position being its: normalposition whereinthe bracket l3 abuts the stop ring I9 -b. i

In the modified form shown inFig. 8, the invention is illustrated as. embodied in a slightly different form of a, conventional automatic shotgun in, which acap 38-, which is threaded tothe end of themagazine l5, islocated'within the forestock 5.-a. In this form, the conventional a tomatic. mechanism may; also. be utilized by-providing a screw 39 which is secured to the cap 38 and extended through a, front wall 5.-.b of the forestock. An adjusting screw 32-0, is provided to abut the lever 29-41, in the same manner as the screw 32, and to further provide a means of adjustment for regulating the distance for which the said lever 29-a and the extension 33-a are rocked as the forestock is moved forwardly to open the stop spring 23-41.

An adjustable stop nut 40 is threaded to the said screw 39 to act as a stop for the forestock which will control the mechanism in the same manner as above described, wherein the forestock abuts the stop shoulder lB-a of the cap 18. The said mechanism, as illustrated in Fig. 8.-is shown in the normal position corresponding to the position in which the mechanism is shown in Fig. 5, wherein the forestock has been moved rearwardly, the lever 29-a has been permitted to rock downwardly, the projection 33-a has been lowered and the lock spring 23-a permitted to close against the outer surface of the sleeve l9-a.

As illustrated in the said modified form, the lever 29-a may be adjustably mounted upon the forestock by means of an adjustable T- shaped pivot member which may comprise a screw shank H that is threaded to the forestock and has a pivot bar 42 by which the lever 29-a is pivotally carried. Adjustment of said lever on the forestock may be made by rotating said T-shaped pivot member and thereby adjustably positioning the lever for the proper operation of the extension 33-a to open the lock spring 23a as the screw 32 is brought into abutment with the lever 29-a.

If desired, the lock spring operating mechanism may be modified, as shown in Fig. 9, by providing a projection tl-a, on the hub 3| and an opening l2-a in the bar 12 so that the lock spring operating lever 29 may not be accidentally rocked to the position shown in Fig. 1 except when the barrel 4 of an automatic firearm is in firing position and the connecting bar II in normal position.

I claim:

1. A firearm comprising a barrel, recoil mechanism, means for changing the bore at the muzzle of said barrel to thereby vary the amount of choke at said muzzle, a forestock enclosing said recoil mechanism and movable relatively to said barrel, and mechanism contained within said forestock and controlled by the movement thereof relatively to the barrel for selectively operating said bore changing means to provide different degrees of choke at said muzzle.

2. For a firearm comprising a barrel having means for adjusting the size of the bore at the muzzle thereof, an adjusting mechanism comprising a bar connected to said bore adjusting means and running rearwardly from said adjusting means along said barrel, a recoil mechanism including stationary means rigidly secured to said barrel, movable means secured to said bar for operating said bore adjusting means, and means for selectively locking said movable means to the stationary means in different positions for changing the said bore adjusting means to provide different degrees of choke at said muzzle.

3. For a firearm comprising a barrel having a sleeve slidable over the muzzle to change the size of bore for varying the degree of choke in said barrel, a choke adjusting mechanism operable from a position at the rear of said barrel and including a member stationary relatively to the barrel, a member movable relatively to the barrel, a bar running along said barrel and interconnecting said movable member with said sleeve, locking means for locking said movable member to said stationary member in different positions relatively thereto, and manually operable means for selectively changing the position of said movable member for adjusting the said sleeve to provide different degrees of choke for said barrel.

4. For a firearm comprising a barrel, a sleeve slidable over the end of said barrel for changing the degree of choke therein, and a forestock movable relatively to said barrel; a choke adjusting mechanism comprising a tie bar connected to said sleeve and extending rearwardly therefrom, and means controlled by movement of said forestock for selectively locking said tie bar to said barrel in different positions relatively thereto to thereby adjust the said sleeve for providing different degrees of choke for said barrel.

5. For a firearm comprising a barrel and a forestock movable relatively to said barrel, a choke adjusting mechanism including a sleeve slidable over the muzzle of said barrel for changing the size of bore at said muzzle, a tie bar secured to said sleeve and extending rearwardly along the under side of said barrel, a tubular member rigidly secured to said barrel, a bracket on said tie bar slidable over said tubular member, and means controlled by movement of said forestock for moving the said bracket relatively to the said tubular member and looking it thereto in difierent positions relatively to the barrel for selectively adjusting the said sleeve to provide different degrees of choke for said barrel.

6. For a firearm comprising a barrel and a forestock movable relatively thereto, a choke adjusting mechanism including a sleeve slidable over the muzzle of said barrel for changing the degree of choke at said muzzle, a tie bar connected to said sleeve and extending rearwardly along the bottom of said barrel, a bracket rigidly secured to said barrel, a tubular member extending from said bracket parallel to said barrel, locking means on said tubular member, a projection on said bar slidable over said tubular member, a locking member carried by said projection and cooperating with said locking means for locking the said projection to the tubular member in different positions relatively thereto, means for moving said projection and tie bar to said different position to cause adjustment of said sleeve, and means operable by movement of said forestock for operating said locking member into unlocked position and permitting said projection to be moved forwardly relatively to the stationary tubular member to thereby move the sleeve to normal position.

'7. For a firearm including a barrel and a forestock movable relatively to said barrel, a choke adjusting mechanism including a sleeve fitting over an exterior surface on the muzzle of said barrel for varying the degree of choke in said barrel, a tie bar connected to said sleeve and running rearwardly along the bottom of said barrel, a tubular member rigidly secured to said barrel, a bracket projecting downwardly from the end of said tie bar and slidable over said tubular member, a spring urging said tie bar forwardly relatively to said barrel for moving the sleeve towards open bore position, a locking member carried by said bracket, means on the tubular member cooperating with said locking member for locking said sleeve in different positions relatively to the barrel, and cam means carried by said forestock and operable upon movement thereof relatively to the barrel to condition said locking member for unlocking said bracket from the tubular member andpermitting. movement of the sleeve to open bore position.

8. For a firearm having a barrel, means for adjusting the choke of said barrel including a sleeve slidable over a tapered portion of the muzzle of said barrel for varying the degree or" choke therein, a tie bar secured to said sleeve and extending rearwardly under said barrel, a tubular member rigidly secured to the barrel, the said tubular member having recesses therein providing a plurality of abutments, a bracket connected to said tie bar and slidable longitudinally on said tubular member, spring means urging said bracket and tie bar forwardly to move the sleeve towards open bore position, locking means including a spring member in the form of a ring carried by said bracket and adapted to close into said recesses in said tubular member for locking the sleeve in different positions relatively to the barrel to adjust the degree of choke in the barrel, manually operable meansfor opening said locking member to permit selective movement of the sleeve to different positions, and means for permitting locking of said sleeve in position by engagement of said locking member with a selected one of said abutments on said tubular member to retain the sleeve in position for providing a selected degree of'choke in the bore ofsaid barrel.

9 In a firearm of the character described comprising a barrel having a muzzle portion adapted for choking; said portion having slits therein and a tapered outer surface, a sleeve slidable over said tapered surface, a tie bar connected to said sleeve and extending rearwardly under said barrel, an elongated member rigidly secured to said barrel, the said elongated member having a plurality of locking abutments, a

projection from the end portion of said bar slidable over said elongated member, spring means urging: said projection forwardly on said member to move the sleeve toward open bore position, a locking member in the form of a spring ring embracing said elongated member and carried by said projection, an operating abutment on said elongated member, a manually operable member slidable relatively to said barrel and elongated member, a lever pivotally secured to saidmanually operable member, an extension on said lever for opening said locking ring to unlock said projection from the elongated member and permit movement of the sleeve toward open bore position uponengagement of saidlever with said operating abutment, and an abutment on said projection" engageable upon rearward movement of said. manually operable member for moving the said projection against the tension of the said spring means and thereby permitting engagement of the locking ring with a selected one of saidlocking abutments on theelongated'membe!" for adjusting the position of the sleeve for a selected degree of choke in'said'barreli 10. A firearm of the character described comprising a barrel, means'including a sleeve" slidable' over said barrel for varying: the degree of choke in the bore thereof, a tie bar extending rearwardly from said sleeve and under the barrel, an elongated member rigidly secured to said barrel, a projection on said tie bar slidable over said elongated member, a plurality of abutments inthe exterior surface of said elongated member, a locking member movable with said projection and adapted to be selectively engaged with. said abutments for locking the-tie bar in difie'rent positions relatively to the barreland thereby adjusting the said sleeve for different degrees of choke in said bore, a forestock slidable relative to said barrel, a lever pivotally carried by said iorestock and depending downwardly, an extension on said lever extending into said locking member, and an abutment carried by said elongated member; the said forestock being manually operable to move said lever into engagement with said abutment and thereby cause liftingofthe extension thereon to open the locking member for disengaging it from the elongated member and permitting the sleeve to be moved towards open bore position, an abutment on said projection, and a separate abutment carried by said forestock for engaging the abutment on the projection and moving said-projection rearwardly to permit the locking. member to engage a selected one of said abutments in the elongated member and thereby position the sleeve for the selected degree of choke in the bore of the barrel.

11. A gun as set forth in claim 10 wherein the abutment on the projection is adjustable to permit the movement of said projection for the proper distance to cause engagement between the locking member and the abutments on the elongated' member.

12. A firearm of the character described comprising a barrel having a tapered exterior surface over the muzzle thereof and slits in the-wall of said muzzle, a sleeve slidable over saidtapered portion for varying the'bore of thebarrel to provide choke-in said bore, a tie bar extending rearwa-rdly from said sleeve and running along the bottom of the barrel,.a; forestock manually movable relatively to the barrel, and means operable by said forestock for selectively positioning the said sleeve along said tapered surface to adjust the degree of choke in said barrel; the said sleeve being threadedto said tie bar to permit longitudinal adjustment. relatively thereto for calibrating for the degree of choke.

13. A firearm comprising a barrel having a tapered surface at the: muzzle thereof with slits in the wall of said muzzle, a sleeve slidable over said tapered surface for closing the bore of said barrel to provide di-fierent degrees of choke therefor, a channeled tie bar threaded to said sleeve and extendingalongthe under side of the barrel inproximity thereto, an elongated member running parallel tothebarreI and rigidly secured thereto, the-saidmember having aplurality of slots therein, the said slots having walls providing spaced abutments along said elongated member, a projection on said tie bar, a locking ring: carried by said projection and slidable" over the-elongated member and adapted to close into said slots for locking. the'projection to'the elongated member, afore'stock manually movable relatively to the barrel, a. lever carried by said forestock, an abutment on said elongated member adapted to engage and roc'k-fs'a'id lever upon movement of the forestock, a projection on said lever movable upon the rocking thereof to open said locking ring and disengage it from thelockingl slot, means urging the projection forwardlyelongated member for positioning said projection in normal position, an adjustable abutment on said projection, an abutment movable with the forestock to engage said adjustable abutment and move the projection rearwardly along said elongated member to selectively engage the locking ring with a locking slot thereon for positioning the sleeve to provide a selected degree of choke in the bore of the barrel, and spring means urging said lever forwardly to retain the projection thereon in normal position and permit closing of the ring into the slot for the selected degree of choke.

14. A firearm as set forth in claim 13 wherein the position of the lever in the movable forestock is adjustable relatively to the forestook to permit 10 proper co-operation with the abutment in the elongated member.

WILLIAM J. HOZA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 10 Number Name Date 653,613 Broyles July 10, 1900 685,669 Broyles Oct. 29, 1901 1,348,750 Schuster Aug. 3, 1920 1,508,605 Legett et al Sept. 16, 1924 1,598,360 Pavek Aug. 31, 1926 2,153,246 Gibson Apr. 4. 1939 

